The cognitive demands associated with choosing whether or not to follow a link from a list of search results has long been noted in the context of general hypertext research. Research on rhetoric of departure and more recent work on information scent or residue highlight the importance of showing readers cues about information that may be found at the destination. Early hypertext systems such as Hyperties provided short summaries or glosses of each link at the bottom of the page, whereas other systems use “tool tips” or “hover text” to show additional content as a pop-up window. Other researchers have explored the use of “fluid links”, and more generally fluid documents, to show additional information about hyperlinks using a variety of different presentation techniques (e.g., inline, inline in smaller font, in the margin, as a textual overlay, etc.) Still yet other research has also explored link previews in the context of general web browsing using ideas motivated by research on magic lens filters. Much of this work on link previews focuses on system architecture and not on usability of the resulting systems. In addition, the work does not specifically address information presentation for search results.
One of the most common presentation techniques for displaying web search results is to show the title, URL and a short summary or gloss of each result. The summaries are sometimes the first few lines of the destination web page. More recently, query-biased summaries, which show sentence fragments that match one or more query terms, have become popular. There is some experimental evidence to support this choice as a means of helping people decide which links to follow, although very few queries were systematically evaluated. The use of key sentences extracted from the text on destination pages has also been tried recently with encouraging results for improving web searching, although again few queries were systematically evaluated. Thumbnails of web pages have also been examined as a technique for providing additional information about the content of destination pages.
Several of these techniques for enhanced content presentation of search results are static, in the sense that they appear for all search results and independent of user interactions. Internet search results are typically displayed as a list conforming to a static style sheet. The difficulty of perusing this list can be exacerbated when screen real estate is limited, as for instance, when using a laptop. When visual space is limited, either, few results are seen, in which case, scrolling may be required to find some relevant results, or result descriptions are abbreviated, in which case, it is often difficult to know whether to follow a particular web link.